Antenna function of a chlorophyll a/b protein complex of Photosystem I

William Ortiz, Eric Lam, Maria Ghirardi, Richard Malkin

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27 Scopus citations


The functional role of a chlorophyll a/b complex associated with Photosystem I (PS I) has been studied. The rate constant for P-700 photooxidation, KP-700, which under light-limiting conditions is directly proportional to the size of the functional light-harvesting antenna, has been measured in two PS I preparations, one of which contains the chlorophyll a/b complex and the other lacking the complex. KP-700 for the former preparation is half of that of the preparation which has the chlorophyll a/b complex present. This difference reflects a decrease in the functional light-harvesting antenna in the PS I complex devoid of the chlorophyll a/b complex. Experiments involving reconstitution of the chlorophyll a/b complex with the antenna-depleted PS I preparation indicate a substantial recovery of the KP-700 rate. These results demonstrate that the chlorophyll a/b complex functions as a light-harvesting antenna in PS I.

Original languageEnglish (US)
Pages (from-to)505-509
Number of pages5
JournalBiochimica et Biophysica Acta - Bioenergetics
Issue number2
StatePublished - 1984
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Biophysics
  • Biochemistry
  • Cell Biology


  • CP I
  • Chlorophyll-protein complex
  • LHCP
  • Light-harvesting complex
  • P-700
  • PS I
  • PS II
  • Photosystem I
  • Photosystem I
  • Photosystem I reaction center polypeptides
  • Photosystem II
  • light-harvesting chlorophyll-protein complex


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